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A-D- STRAW.

METHOD OF COATING MOLDS. APPLICATION FILED MIG-30' 1920.

1,420,888, PatentedJupe 27, 1922.

INS/ENTER warren starts arem OFFICE.

narnnnns nsrnam or WAUSEON, OHIO, Assrenon, BY ivinsn-E ASSIGNMENTS, T0 run nusnar n. lu'rnas COMPANY, or TOLEDO, OHIO, A ooiaronarron'or' OHIO.

Specification of Letters Patent.

' l METHOD OF COATING lVIOLIDS.

Patented June 27, 1922.

Application filed August 30, 1920. Serial No. 406,908.

ing to be a full, clear, and exact description of the invention, such as will enable others, skilled in the :art to, which it appertains to.

make and use'thesame, reference being had to the accompanying.drawings, and to the characters of reference marked thereon,

which form a part of this specification.

The invention! relates to the metal casting art and is directed to the treatment of molds with the oxides of metals having low oxid1zing temperaturesto produce deposits of the;

oxides upon the surfaces of the mold so that pitting of the mold and casting is prevented and the metal, while cooling from the liquid to the solid state, is permitted to conform: closely to the shape of the mold, whereby;v smooth, perfectly formed castings are pro--.

duced.

I have found that surfacing thematrix of the mold with zinc oxide is ofparticular value when used in casting ferrous metals in molds having their cavity walls. formed of iron, since the zinc oxide will efficiently protect the surface of the mold and produce.

smooth substantially perfect. castings. V The invention may be used to: deposit on the mold surfaces the oxides OfVZtlflOUS metals for the purpose of protecting-the molds; from the action of the molten-metalor mete;

als and producing smooth substantially. per: fectly formed castings. The devices shown in the drawings are merely illustrative of means for carrying out my invention, and may be greatly modified by those skilled in the art.

Figures 1 and 2 illustrate different means for applying metallic oxides to mold sections.

In carrying out the method of treating molds'by my invention I cause to be gasified or vaporized a suitable metal that will, while in a gaseous state, become oxidized by at mospheric oxygen. I prefer to use a metal that will form a heat insulating oxide that will readily deposit on and adhere to the surface of the mold whether the mold is cold or hot.

In Fig. 1 a suitable burner, such as the burner 13, is provided, which is connected With a suitable source of fuel gas supply through the pipe 1. The burner 13 may be located in or surrounded by suitable confining walls 2 that form the chamber 12. A receptacle 1 1 is so located within the chamber 12 as to be heated by the flames from.

the burner 13. The receptacle 14 is completely closed, except for the air inlet 23 and theoutlet pipe 16 that forms a nozzle for the. gaseous material that issues from the container 14:. Since the gas in the container 14 is confined, the vapor will be subjected to some pressure and issue from the nozzle 16 with a rapid movement, which Will cause the oxide to penetrate to all parts and crevices of the mold.

A hopper 15 is connected to the top of the container 14 and is closed at the bottom by a pivoted plate 3, that may be operated by means. of the rod 11 and the arm 4, the latter being rigidly connected to the plate 3. The top of-the hopper 15 is closed by a suitable cover 18. Zinc filings, for example,

may beinsertedin the hopper 15, while the lower end of the hopper is closed by the plate 3. Thus the container 14: is kept closed, except through the nozzle 16, while the hopper15 is being filled. When the hopper hasbeen filled or partially filled with zinc filings the cover 18 may be closed and theplatelii opened. The filings will then fall intov the container 14 where they will be heated by the burner 13 until the vapor rises tl'irough the nozzle 16. The mold is preferably located well above the nozzle to give ample opportunity for the oxygen of the air to attack the'zinc vapor and oxidize the vapor, and yetnot so remote but what the flocculent oxide will deposit 011 the surface of the mold. This position is substantially as illustrated in the figure. If pressure greater than that produced through the formation of the vapor in the closed chamber is desired, it may be secured by admitting air under pressure through the pipe 23. If air is thus used the metallic oxide will be formed in the container and will issue through the nozzle.

In the form of the device illustrated in Fig. 2 fuel gas enters the burner 6 through a suitable pipe 19. Within the burner6 is located a sleeve 20 which extends to near the top of the burner 6 and forms an annular opening where the fuel is ignited. Within use the sleeve 20 is located a tubular member 7 having a bore somewhat larger in the upper end than through the remainder of its length. The upper end is closed by a cap having small openings 9 through which metallic gas or vapor may be emitted. A rod 8 of zinc, for example, is passed up through the tubular member '7 and is heated in the small chamber formed by the larger bore of the tubular member. To the upper end of the tubular member is secured a flaring or conical shaped plate 10. The flame 21 of the fuel gas rises around the outer edge of the flaring plate 10 and forms an enclosing envelope, as shown in the figure, while the zinc is heated and is caused to vaporize. The zinc passes upwards in a. stream, as indicated at 22, towards the mold 5, placed over the flaring plate 10, upon which a coating of zinc oxide is deposited.

In the claims I use the word broad term to cover and include and vapor.

1. The method of treating molds for casting metals, which consists in directin a. stream of metallic gas towards the sur ace of the mold in the presence of oxygen, and depositing the oxide of the metal on the BS 38 a 0th gas mold.

2. The method of treating molds for easting metals, which consists in directin a stream of metallic gas towards the sur ace of the mold in the presence of oxygen, and depositing on the molding surface of the mold a heat insulating finely divided material.

3. The method of treating metal molds for casting metals, which consists in directing a stream of metallic gas and its oxide towards the surface of the mold, and depositing the oxide on the surface of the mold.

4. The method of treating metal molds for casting metals, which consists in directing a stream of metallic gas in the presence of oxygen towards the molding surface and depositing an oxide of the metal in a finely divided state on the surface.

The method of treating metal molds for casting metals, which consists in reducing a metal to an oxide and directin it in a finely divided state towards a mol and depositing it in the form of a finely divided oxide.

(3. The method of treating metal molds for casting metals, which consists in directing a stream of zinciferous material towards the surface of the mold, and depositing a zinciferous material on the mold.

7. The method of treating metal molds for casting metals, which consists in directing a stream of zinc gas and its oxide towards the mold, and depositing a zinciferous material on the mold.

8. The method of treating metal molds for casting metals, which consists in directing a stream of zinc gas towards the surface of the mold, in the presence of oxygen, and depositing a heat-insulating finely-divided zinc oxide on the surface of the mold.

9. The method of treating a metal mold for casting metals, which consists in directing a stream of zinc oxide against the surface of the mold and depositing it in a. finely divided state on the molding surface.

10. The method of treating metal molds for casting metals, which consists in directing a stream of zinc gas towards the molding surface in the presence of oxygen, and depositing zinc oxide in a finely divided state on the surface.

11. The method of treating metal molds for casting metals, which consists in reducing zinc to an oxide and directing it in a finely divided state towards a mold, and depositing it in the form of a finely divided oxide.

12. The method of preparing a mold formed of a ferrous metal to prevent the adherence of a ferrous metal castin thereto, which consists in directing a heate zinc gas towards the surface of the mold in the presence of air and depositing zinc oxide on the molding surface.

In testimony whereof I have hereunto subscribed my name to this specification.

ARTE EMES D. STRAW. 

